In October 1871 a fire swept through Chicago, destroying much of its densely built wooden core, killing around 300 people and leaving roughly a third of the population homeless. The rebuilding, driven by booming commerce and rising land values, used fire-resistant steel, brick and stone and adopted stricter building codes. In the decades that followed, architects of the Chicago School exploited steel framing and the safety lift to build the first tall office buildings. The cleared and rebuilt downtown became a proving ground for new construction technologies.
It cleared the ground for what became the world's first vertical business district and the birthplace of the skyscraper. The episode linked disaster, regulation and technology in producing the modern high-rise downtown.